1. Field of the Invention
The present invention relates to a separation method and a separation apparatus.
2. Description of the Related Art
Hitherto, a method for separating and recovering olefin from a mixture of paraffin and olefin with a separation membrane including a porous substrate and a zeolite layer arranged on a surface of the substrate and/or in a surface layer portion of the substrate has been reported as a separation method (for example, see PTL 1 and NPLs 1 and 2). PTL 1 states that in the case where a Si/Al ratio in a zeolite layer is 1.3≤Si/Al≤3.5 and where the separation factor α of the zeolite layer for a water-isopropanol mixture containing 15% to 30% water by weight is within a predetermined range, a separation membrane is highly selectively permeable to olefin and has good durability. NPL 1 states that propylene/propane or ethylene/methane separation can be performed with an FAU-type zeolite membrane. NPL 2 reports a method for separating one of olefin and paraffin from an olefin-paraffin mixture with a AgY-type zeolite membrane formed by ion exchange of a NaY-type zeolite membrane.